This invention relates generally to the field of data storage devices and more particularly but without limitation to flexible ribbon cable interconnect apparatuses in an actuator assembly.
Modern data storage devices such as disc drives are commonly used in a multitude of computer environments to store large amounts of data in a form that is readily available to a user. Generally, a disc drive has a magnetic disc, or two or more stacked magnetic discs, that are rotated by a motor at high speeds. Each disc has a data storage medium comprising a surface divided into a series of generally concentric data tracks where data is stored in the form of magnetic flux transitions.
A data transfer member such as a transducer is moved by an actuator assembly to selected positions adjacent the data storage surface. The active elements of the transducer are supported by suspension structures (or xe2x80x9cflexuresxe2x80x9d) of the actuator assembly. The active elements are maintained a small distance away from the data storage surface as the transducer flies upon an air bearing generated by air currents caused by the spinning discs.
Each transducer is typically provided with separate read and write elements, with a common configuration utilizing a thin film, inductive write element and a magneto-resistive (MR) read element. Data are written by passing a write current through the write element, with the write current generating a time-varying magnetic field which accordingly magnetizes the disc surface. Previously written data are read using the read element to transduce the selective magnetization of the disc to generate a read signal which is received by a read channel to reconstruct the data.
The actuator assembly operates within a negative feedback, closed-loop servo system. In this manner, the actuator moves the transducer radially over the disc surface for track seek operations and holds the transducer directly over a track on the disc surface for track following operations. A servo controller samples the position of the transducers relative to some reference point and generates an error signal based upon the difference between the actual position and the reference position. This error signal is then used to drive the transducer to the desired reference point, typically by demanding a current through a voice coil motor (VCM) which forms a part of the actuator assembly.
Typically, the control electronics are situated in a circuit board attached to the device enclosure. A flexible connector electrically connects the actuator assembly to the circuit board in a manner permitting the movement of the actuator body, or e-block, between the innermost and outermost data tracks. One type of flexible connector is a looped ribbon cable that is fashioned to expand and contract as the e-block moves substantially without resistance on the actuator assembly.
Ribbon cable type electrical interconnects are recently replacing the prior use of small wires connecting the transducer to the flexible connector. In a preferred solution, a longitudinal opening is defined in the e-block that is aligned with a lateral face of one of the actuator arms. One end of the interconnect is fixed to the actuator body and electrically connected to the flexible connector. The other end of the interconnect is fixed to the arm and electrically connected to the transducer. A medial portion electrically connects the ends, and a segment of the medial portion is receivingly engaged within the e-block opening for constraint.
A potential problem exists with the interconnect medial portion being loosely constrained within the e-block opening. Namely, air currents passing over the e-block can impart forces creating vibration in the interconnect medial portion. These vibrations can result in nonrepeatable runnout (NRRO) errors in the data reading and writing procedures.
One proposed solution involves using a bonding material, such as an adhesive or an epoxy, to fix the interconnect medial portion to the e-block within the opening. Although effective in reducing vibrations, using a bonding material necessarily involves employing complex and problematic manufacturing procedures.
On the other hand, it has been determined that a retaining member can be utilized cooperatively with the interconnect to wedgingly engage the interconnect medial portion within the e-block opening. The retaining member can be a feature of the interconnect, such as a tab juxtaposed adjacent one edge of the medial portion and foldable toward the medial portion. The tab and medial portion cooperate to define a resiliently compressible member that is attachable in the e-block opening. It is to these improvements and others as exemplified by the description and appended claims that embodiments of the present invention are directed.
Embodiments of the present invention are directed to an interconnect apparatus for connecting a transducer to a flexible connector in an actuator assembly of a data storage device. The actuator assembly has a moveable actuator body, or xe2x80x9ce-block,xe2x80x9d and an arm extending from the body. The body defines a longitudinal opening aligned with the arm and associated with the placement of the interconnect apparatus. The interconnect apparatus comprises a proximal end fixable to the actuator body and electrically connectable to the flexible connector; a distal end fixable to the arm and electrically connectable to the transducer; a medial portion electrically connecting the ends, a segment of the medial portion disposable within the actuator body opening; and a retaining member interposable between the medial portion and the actuator body within the opening, adapted for fixing the medial portion to the actuator body without using a bonding material.
In one illustrative embodiment the retaining member comprises a tab juxtaposed adjacent the medial portion and operably foldable toward the medial portion. Accordingly, the folded tab and medial portion generally define a cross-sectional shape characterized by a resilient compressible member receivingly engageable within the opening. Preferably, the folded tab and medial portion define a compressible member wedgingly engageable within the opening.
In one illustrative embodiment the actuator assembly has two arms extending from the actuator body, wherein a first interconnect apparatus is attachable to one of the arms and a second interconnect apparatus is attachable to the other arm. Both interconnect apparatuses pass through the same opening in the actuator body. The respective tabs can be clearingly longitudinally staggered so as to prevent an overlapping engagement therebetween. In one illustrative embodiment each of the tabs is receivingly engageable between the interconnect apparatuses. The tab can be attached at one edge to the interconnect apparatus medial portion; alternatively, the tab can be unitarily formed as a portion of the interconnect apparatus.
In one aspect of the embodiments of the present invention an actuator assembly for a data storage device is contemplated. The actuator assembly comprises a moveable actuator body comprising an arm extending from the body; a transducer supported by the arm to read data from and write data to a data storage medium of the data storage device; a flexible connector connecting a printed circuit board of the data storage device and contact terminals supported by the actuator body; and an interconnect apparatus electrically connecting the transducer and the flexible connector, wherein the actuator body defines a longitudinal opening aligned with the arm and associated with the placement of the interconnect apparatus.
The interconnect apparatus comprises a proximal end fixed to the actuator body and electrically connected to the flexible connector; a distal end fixed to the arm and electrically connected to the transducer; a medial portion electrically connecting the ends, a segment of the medial portion disposed within the actuator body opening; and a retaining member interposed between the medial portion and the actuator body within the opening, fixing the medial portion to the actuator body without using a bonding material.
In one aspect of the embodiments of the present invention a data storage device is contemplated, comprising an actuator assembly operably coupled with a data storage medium in a data reading and writing relationship; and means for reducing vibration by fixing a medial portion of an electrical interconnect to the actuator assembly without using a bonding material.